We plan to continue our studies on the structure of the chromatin fiber. In particular, we shall attempt to assemble nucleosomes on specific DNA sequences (5S RNA genes, histone genes, etc.) to determine if in vitro reconstitution results in the same phase relationship observed in vivo. If faithful reconstitution occurs in vitro, we shall proceed to alter the DNA sequence (using deletions, insertions, etc., in the particular DNA plasmids) to pinpoint the DNA signals responsible for the observed phase relationship between DNA and nucleosomes.